ML20033C419
| ML20033C419 | |
| Person / Time | |
|---|---|
| Site: | 07000371 |
| Issue date: | 11/09/1981 |
| From: | Bidinger G NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Kirk W UNITED NUCLEAR CORP. (SUBS. OF UNC, INC.) |
| References | |
| NUDOCS 8112030151 | |
| Download: ML20033C419 (4) | |
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i ATTN: Mr. William F. Kirk, Manager
't-Nuclear and Industrial Safety 67 Sandy Desert Road
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~^" e Gentlemen:
We have reviewed your amendment application and supplements dated September 20, 1979, August 8,1980 and July 30, 1981. The enclosure to this letter identifies information which is needed to supplement or otherwise clarify the application. Most of the issues in the enclosure were discussed on Octcber 15, 1981 with Mr. Neumann and Mr. Gutman of your staff during a meeting in Silver Spring, Maryland. Several new items have been included herein as a result of information provided during the meeting.
We will continue our review upon receipt of the additional information.
Sincerely.
Original signed by GeorSe H. Bidinger G. H. Bidinger Uranium Process Licensing Section Uranium Fuel Licensing Branch Division of Fuel Cycle and Material Safety
Enclosure:
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NRC FORM 318 hoe 8C)NRCM O2 40 OFFICIAL RECORD COPY
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Questions Re The September 20, 1979 Application and August 8, 1980 and July 30, 1981 Supplements I.
The numbers below refer to Part I Sections 3.9.1 and 3.9.2 The " safe value" for individual units should be based on actual compounds to assure that the H/U-235 ratio, compound density, w/o alloy, and sur. face density relationships are not non-conservative.
The criteria for calculating these parameters for starting materials and fabricated parts should be described.
Sections 3.9.4 and 3.9.6:
These sections as written would authorize UNC to generate new SIU's by-the density exponent method and KEN 0.
It is our understanding that the actual intent of UNC is to use only the density exponent method. The two sections should be revised to clearly identify as well as limit the analyses which can be performed without license amer.dment.
If new curves or extensions of existing curves are to be added t'o Figure 3.9-1 thru Figure 3.9-5 without a license amendment, the density exponent method must be shown to be applicable for the full H/U-235 range and the range of alloy content in the SIO.
In either case, we understand that KENO would be used only to verify the density exponent values.
Section 3.9.3 The 8-inch edge-to-edge vertical separation must be justified for geometries over a full range of values (H/U-235, H/D, etc.).
In a similar manner, criteria for minimum horizontal separation must be established.
l It should be noted that the calculations in Section II for the array of spheres do not justify the conclusion that a minimum vertical separation of 8 inches, l
edge-to-edge, is adequate. Plotting the k-effective values versus H/D will show that the conclusion is not valid.
Section 3.9.5 This section should be revised to indicate that arrays (including single unit arrays) spaced by the surface density method will be isolated from units in arrays spaced by other analytical methods, e.g., solid angle.
Sections 3.9.3 and 3.9.6 and Table 10.0-I, Note 6 In sections such as 3.9.3 and 3.9.6 where KEN 0 calculations are referenced to support the criteria, the input and output of the KEN 0 calculations must be provided.
If KEN 0 is used for a parametric survey, only changed parametric values and k-effective plus sigma values need be submitted for all but the first calculation, o
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. Figures 3.9-6 and 3.9-7 The relationship between the surface density curves and the maximum keff of 0.928 (from Section'3.9.3) should be developed by parametric studies
.(in Section II) considering unit' reactivity, unit shape, unit composition, and in-plant environmental conditions.-
Section 8.2.3.4.
The criteria in this section is based on a maximum k-effective and limits on physical size and minimum vertical separation. The criteria should specify a k-effective for each unit or should specify the method to determine the keff
- for specific units. Minimum horizontal separation between back-to-back rows must be provided.
-- Section 3.9.1.1 The safety factors in this section have been used for purposes of nuclear criticality safety for uranium solutions wnere the H/U-235 ratio is greater than 20. - These safety factors are not universally applicable to high density uranium-water mixtures because the actual change in physical dimensions of small critical systems with safety factors of 1.1,.1.2 or 1.3 is. too small to be controlled in a fuel production area.
These safety factors should be limited to uranium solutions and new factors provided for high density uranium-water. mixtures.
Figures 3.9-6 and 3.9-7 and Table 3.9-3 These figures and-table provide spacing criteria for safe units as a function of the H/U-235 ratio.
Please provide your criteria for controlling and maintaining the H/U-235 ratio.
II. The numbers below refer to Part II:
Sections 3.9-1, 3.9-2 and 3'.9-3, The analyses for the welder, furnace and X-ray units can not be confirmed because the materials, material zones, and three dimensional cell sizes are not'provided in sufficient detail to permit independent review and con-firmation ~ of results. Two of the associated sketches (3.9-2.1 and 3.9-2.2) appear to be misnumbered.
Section8.2.1.5 The criticality safety evaluation fails to satisfy the minimum vertical edge-to-edge spacing criteria of Section 8.2.3.4, Part I.
The evalcation takes credit.for nuclear poisons which have not been demonstrated to be present in units to be placed on the storage racks. The' cell dimensions are not consistent with the minimum dimension in Section 8.2.3.a. Dart I; this-would tend to underpredict k-effective. This section should be revised accordingly.
<... Analysis 3.9-1 It is not clear why full density water is used as a reflector at the cell boundary rather than as a tight-fitting reflector about the welde,r.
It is not clear why 0.37 g/cm3 is used as the density of water throughout the cell in part of the analysis.
Finally, cell space dimensions are given as 2 feet and 4 feet.
It is not clear what criteria ane used to establish these values or how the welder-fixture is crisntsd with respsct"to thdse dimensions. ' As s umo'-
tions'used in this section should be' explained and justified.
Section 10. A.1.1 The bulk density and the H/U-235 ratio for incoming material do not meet the criteria for Table 3.9-1, Part I.
The sealed cans of incoming material are assigned 0.5 ft2 spacing area. This does not provide sufficient spacing for flooding, doJble batching, or interspersed moderation.
This type of error is repeated several -times in this section. This section shculd be revised to establish minimum separation in both the vertical and horizontal directions.
The blending operation appears to permit the introduction of a' safe unit in a spacer tray, based on moderation control, ir.Ro a box containing liquid (alcohol). The presence of the liquid would appear to violate the basis for safety of the dry unit in the spacer tray. The safety evaluation should demonstrate the double contingency principlb for this operation.
Interpolation of limits for 7 w/o material in this demonstration for element fabrication is not provided for in the criteria in Section I.
Values should be read from the higher w/o curves as presented in the referenced figures.
In addition, changing the w/o alloy by considering elements in different orientation indicates that criteria for figures in Section 3.9 of Part I inadequate or thatibcnam being misapplied in Part II.
This raises questions on methods to calculate the H/U-235 ratio, w/o alloy, and reflector effects.
This section should be revised in accordance with criteria used to develop curves in Section 3.9, Part I.
See comments above concerning Sections 3.9.1 and 3.9.3, Part I.
The analysis for the special cleaning and pickling fixture does not fall within the criteria in Part I for unit subcriticality or unit spacing. The analysis should be shown to meet criteria in Part I of the application.
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